Fluid-pressure-actuated motor



T. LAURENT. l FLUID PRESSURE ACTUATED MOTOR.

APPLICATION FILED SEPT. 22, 19|?.

Patented Apr. IIS, i922.

IMI

narran statits THOMAS LAURENT, OF NEVI' YORK, N. Y., `ASSG'N'OR TONATIONAL PNEUIVIATIC COMPANY, OF NEXV YORK, N. Y., A COREORATON Ol? WESTVIRGINIA.

FLUD-PRESS'URE-ACT'UATED MOTOR.

Specification of Letters Patent.

Patented Api'. f8, i922.

Application filed September 22, 1917. Serial No. 192,650.

To all whom. t may con-cern:

Be it known that I, T'HoMAs LAURENT, a citizen of the United States',residing at New York,- county of New York, State of New York, have` madea certain new and useful Invention in Fluid-Pressure-Actuated Motors, ofwhich the following is a specification.

This invention relates to iluid pressure actuated motors.

The object of the invention is to provide a fluid pressure actua-tedmotor of standard construction with a type of cushioning connectionassociated therewith, and to provide means for insuring the cushioningaction of said connections.

A further object of the invention is to insure a proper sequence ofoperation of the controlling means of the motor.

Further objects of the invention will appear more fully hereinafter.

The invention consists substantially in the construction, combination,location, and relative arrangement of parts, all as will be more fullyhereinafter set forth, as shown by the accompanying drawing, and finallypointed out in the appended claims.

Referring to the drawing Fig. 1 is a view in elevation of a standardtype of fluid pressure motor with diagrammatic piping system and valvecontrol of the same.

Figs. 2 and 3 are views of the valve and valve seat for variouspositions of the valvev on its seat.

Fig. l is a sectional view taken on the line 4 4 of Fig. 3 and lookingin the Adirection of the arrows.

Fig. 'is a bottom face view of the valve employed in accordance with myinvention;

Fig. Gis a sectional view taken on the line 5 5, Fig. 5, and looking inthe direction of the arrows.

The same part is designated by the same reference numeral wherever itoccurs throughout the several views.

In pneumatic engines or motors there are in practice three differenttypes. In all types it is necessary to have some automatic means ofcushioning or retarding the motion of the engine towards the `end of itsstroke. In the one type, which l will call the first type, the pressurethat has operated the engine in one direction is not liberated at theend of the stroke, but is retained until the moment the engine isreversed when part of this pressure is exhausted, a sufficient portionbeing retained however to cushion the final motion of the engine.

ln the second type, the pressure is automatically exhausted at the endof the travel of the engine, and when the engine is reversed the actionis obtained by compressing the free air in that end of the engine. 0fnecessity the relative arrangement and size of the exhaust ports thatare suitable for the first type would be unsuitable for the second typeas the pressure of the air on which the cushioning feature depends ismuch lower in the second type than in the first type.

The thirdg type of engine employs exterior auxiliary means forcushioning` the engine at the limits of its movements. This inventionhas reference to the first type of engine above described, and to thatform of the same in which the controlling valve is manually operated.When the valve is operated electrically 'or pneumatically it is movedinstantly from one desired position to another, but when manuallyoperated it is possible for it to be moved slowly andgradually andtherefore conditions may rise due to the position of the valveintermediate its proper extreme positions that could not arise with apower operated valve.

ln ordinary practice the valve is moved from one extreme position to theother, and heretofore, therefore, no exact detail has been followed inregard to the sequence with which the various ports were opened orclosed, it being deemed sufficient in one extreme to have one piston orcylinder end open to pressure and closed to exhaust and the other pistonor cylinder endopen to exhaust, usually through a more or lessrestrictive opening, and closed to pressure.

ln practice, however, as for instance, when used to operate doors onstreet cars, it has been found that sometimes the conductor will creephis control handle little by little from one extreme position to theother withthe result that the retarding pressure in either end of thecylinder is allowed to escape before the door starts to move, and thesize of the cushioning' ports being suited to an engine that cushions onconsiderable pressure, there would not remain enough ie, e.

" the passage 21 controlli-ng the exhaust and pressure in the exhaustend of the engine to properly cushion its motion, and the door wouldslam open or shut. lt is among the special purposes of my presentinvent-ion to so rela-te the position of the ports that in :moving thevalve from one extreme to the other, the following sequence isfollowed 1. rllie end of the cylinder that has been open to exhaust hasthe exhaust cut off while the other end of the engine still remains opento pressure.

2. The end formerly open to exhaust then becomes opened to pressure. Theother end still remaining open to pressure. T his leaves both endsclosed to exhaust and both ends open to pressure. This is the central orneutral position of the valve.

rlhe end thus far continuously open to pressure is thenclosed topressure.

1l. The end which was originally open to pressure and which becameclosed in its third position nowbeconies open to exhaust.

lt will be seen, therefore, that at no position of the valve can thepressure blow through to exhaust, kand that. at the moment one end ofthe engine is commencing to be open to exhaust, the other end hasalready become open to pressure, so that the engine instantly respondsto the pressure acting against the lessened pressure at the exhaustingend, and the proper action of the cushioning effect is obtained.

Referring to the drawing wherein l show one embodiment of my invention,1 designates the fluid pressure actuated motorof the usual or standardconstruction. My invention is not concerned in the specific type ofmotor employed, but l show a standard type which consists of cylinders2, 3, in which operate the pistons 4l, 5, which pistons Aare connectedby raclr bar 6, which rack bar meshes with the gear segment 7 wh'icli isconnected to the arm S, which in turn controls the door or 'the movingbody. The respective ends of the cylinders 2, 3, are connected by pipes9, 10, to the ports 11, 12, respectively of the valvel seat 13.

Ports 14: and 15 of the valve seat 13 lead into the cylinders .2, 3,through pipes 16 and 17 respectively, Vand terminate in ports 18 and 19,which are uncoveredby pistons 1l, 5, at the limit of their travel incylinders Fluid Vpressure is supplied to the valve andvalve seatthroughport 19 and the port 20 of the valve seat leads to exhaust. The

valve seat thus far described isrof the usual and standard type, and thevalve 30v which operates on the saine lis Vlikewise of the usualstandard typeV provided with the usual passages 21 and 22 inits seatingface,

Y the passage 22 controlli-ng the supply. rlhe passage '21 is Vprovidedwith auxiliary passagesv of `smaller relative vsize 24,125, which areprovided at Stlieir .ends with Vrelatively small ports 26 and 27, whichports are adapted to communicate with ports 11 and 12 respectively whenVthe valve 30 is turned in one direction or another to its extremeposition to operate the mot-or in onel direc.- tion or the other.

The operation of the system is obvious. lVith the valve in the positionshown vin Fig. o, which is its central or neutral position, 1t will beseen that both ends of the cylinder are closed to exhaust inasmuch asnone of the ports 14, 15, 11, or 12, arein communi.- cation with theexhaust port 20, the fluid pressure is allowed to flow from port "'19,passage 22, through port pipes 9 andv 10 to` both ends of thecylinder.`When the Valve is shifted towards the position shown in Fig. 2 port 12becomes closed to the supply aiid port 11 remains open thereto soY thatwith the pressure removed .from the piston 5 the engine starts itsvmovement to 4move the pistons 4 and 5 towards the right.

lhen it has reached its extreme position, namely, that illustrated inFig. 2, it will be seen that the port 15 has become opened to 'exhaustthrough 'passage 21., and that there is a free exhaust from the cylinder3 through pipe 17 to exhaust until the piston 5 closes` the port 19.rFhe restricted port 27 however is now in communication with port 12 andpipe 10 to theend of the cylinder 3 so that the remaining movement ofthe motor is against the restricted ex'-V haust of the fluid pressurewhich remains in they cylinder thereby insu-ringrthe cushioning action.ll

To operate the engine in theother direction from this position of the.Vvalve itv will be seen that the valve will have to pass through neutralposition and will have to insure a supplyofpressure to the exhaustthrough both ends of the cylinder before either end can be exhaustedthereby rendering the manual operation of this type'of .proper vfluidpressure motor or engine a proof against intentional or accidental Ymisuse to prevent the proper functioning of the cushioning meansemployed in connection therewith. v' y Having now set forth the objectand na-V ture of my invention, what l elaiin as'iiew and useful, and ofmy owninvention, 'and desire to secure by Letters Patent, is,--v Y 1.The combination with a fluid pressure motor compri-sing cylinders,pistons operating in said cylinders, a pipe line leading to the end ofeach of sai-dcylin-ders, a valve controlling said pipe line, Aa sourceof fluid pressure supply, and' an exhaust port controlled by said valve,means forestablish'- ies lll)v izo ing communication lbetween reach,Y ofsaid pipe lines with either said exhaustfport vor said sourcejof' fluidlpressurel supply, and

pressure fromfsaid source to one of said l,means vfor preventing theadmission vof fluid cylinders until said cylinder has been closed toexhaust, and for admitting pressure to said cylinder before the supplyof fluid pressure to the other cylinder has been cut ofi', and in theinitial operation from extreme position whereby a cushioning action issecured.

2. The combination with a fluid pressure motor comprising cylinders,pistons operating in said cylinders, a pipe line leading to the end ofeach of said cylinders, a valve controlling said pipe line, a source offluid pressure supply, and an exhaust port controlled by said valve,means for establishingcommunication between each of said pipe lines witheither said exhaust port or said source of fluid pressure supply, meansfor normally admitting fluid pressure to both of said pipe lines andprior to closing one of said cylinders to exhaust in initiating theoperation of the motor from its extreme position whereby a cushioningvaction is secured.

3. The combination with a fluid pressure motor comprising cylinders,pistons operating in said cylinders, a pipe line leading to the end ofeach of said cylinders, a valve controlling said pipe line, a source offiuid pressure supply, and an exhaust port controlled by said valve,means for establishing communication between each of said pipe lineswith either said exhaust port or said source of Huid pressure supply,means for normally admitting fluid pressure to both of said pipe linesand for closing said cylinder to exhaust when said valve is in itscentral or neutral position, and means when said valve is moved towardsoperative position for shutting ofi" the supply of pressure from one ofsaid cylinders before opening said cylinder to exhaust in initiating theoperation of the motor from its extreme limit of action in eitherdirection.

4. In a fiuid pressure actuated motor, comprising cylinders, pistonsoperating in said cylinders, and means for supplying fluid pressure toand the exhaust thereof from said cylinders, ports for controlling thesaid supply and exhaust of fluid pressure to and from said cylinders, amanually operated valve for controlling said ports, and means forsupplying fluid pressure to one of said cylinders prior to the movementof the piston therein in exhausting direction to cushion the movementsof said piston irrespective of the position of the valve when movedtowards an operative position.

5. ln a fluid pressure actuated motor, comprising cylinders, pistonsoperating in said cylinders, means for supplying fiuid pressure to andthe exhaust thereof from said cylinders, ports controlling the saidsupply and exhaust of fiuid pressure to and from said cylinders, amanually operated Valve for controlling said ports, and means forsupplying fiuid pressure to one of said cylinders prior to the initialmovement of the piston therein in exhausting direction to cushion themovements of said piston irrespective of the length of time consumed inmoving the valve to complete operative position.

6. ln a iuid pressure actuated motor, comprising cylinders, pistonsoperating in said cylinders, and means for supplying fluid pressure toand the exhaust thereof from said cylinders, a valve for controllingsaid fluid pressure comprising means for supplying fluid pressure to onecylinder, and opening the second cylinder to exhaust when the valve isat one limit of its movement and means controlled by the movement of thevalve towards its other limit of movement for successively closing saidsecond cylinder to exhaust, then supplying Huid pressure to said secondcylinder, then shutting ofi' the supply of fluid pressure to said firstcylinder, and finally opening said first cylinder to exhaust whereby acushioning action is secured.

7. In a fluid pressure actuated motor, comprising cylinders, pistonsoperating in said cylinders, and means for supplying fluid pressure toand the exhaust thereof from said cylinders, a valve for controllingsaid fluid pressure comprising means for supplying fluid pressure to onecylinder, and opening the second cylinder to exhaust when the valve isat one limit of its movement, and means controlled by the movement ofthe valve towards its other limit of movement and irrespective of thespeed of movement thereof for successively closing said second cylinderto exhaust, then supplying fluid pressure to said second cylinder, thenshutting off the supply of fluid pressure to said first cylinder, andfinally opening said first cylinder to exhaust whereby a cushioningaction is secured.

ln testimony whereof l have hereunto set my hand on this 20th day ofSeptember A. D., 1917.

THOMAS LAURENT.

